Python regex group matches shows extra empty string

Question

I want to get the date followed by DATE FILLED and REFILL from my text. Ordering of DATE FILLED or REFILL is not fixed. And date pattern can be:

6/23/20
6-23-20

My Python scripts is:

expiration_date_regex = re.compile(r"(USE\s+BY.*(?P<expiration>\d{1,2}/\d{1,2}/\d{2,4}))|(DATE\s+FILLED.*(?P<date_filled>\d{1,2}/\d{1,2}/\d{2,4}))", re.M)
find_matches(expiration_date_regex, text)

def find_matches(regex, text):
    matches = regex.findall(text)
    for match in matches:
        print(match)

My text is:

CVS pharmacy
713-217 HsonSt
OTY: 90
REFILL 0 Refills
PRSCBN. A Beil
DATE FILLED 6/23/20
USE BY. 6/23/21
RPH Bill Liu
MFR AUROBINDO PHARM
ST DEA BC2236645
This is a WHITE
REDTME

But I'm getting output something like this, output is almost reasonable but I don't understand what do those first two empty strings means in the first tuple? same goes for last two string of the second tuple. It looks something like bitmask:

('', '', 'DATE FILLED 6/23/20', '6/23/20')
('USE BY. 6/23/21', '6/23/21', '', '')

Why not use simpler: (USE\s+BY|DATE\s+FILLED).*(?P<date>\d{1,2}/\d{1,2}/\d{2,4}) — anubhava
– anubhava, Commented Jan 2, 2021 at 6:01
Thanks @anubhava your comment gives a solution. I had few question how can I handle if Use by and date fill is different date pattern? Is it better to use a single regex with group or write different for each? My use case is I'm getting those texts from an OCR and then finding my required patterns. Sometimes I may get Dat Fill instead of Date Filled — Shahrear Bin Amin
– Shahrear Bin Amin, Commented Jan 2, 2021 at 6:17
Or may be: (?i)(USE\s+BY|DATE\s+FILL(?:ED)?).*(?P<date>\d{1,2}[-/]\d{1,2}[-/]\d{2,4}) — anubhava
– anubhava, Commented Jan 2, 2021 at 6:21
Thanks again @anubhava it worked. Hope to read your book soon. — Shahrear Bin Amin
– Shahrear Bin Amin, Commented Jan 2, 2021 at 6:29

anubhava · Accepted Answer · 2021-01-02 06:31:16Z

3

Converting my comment to answer so that solution is easy to find for future visitors.

You may use this regex:

(?i)(USE\s+BY|DATE\s+FILL(?:ED)?).*(?P<date>\d{1,2}[-/]\d{1,2}[-/]\d{2,4})

RegEx Demo

RegEx Details:

(?i): Enable ignore case mode
(USE\s+BY|DATE\s+FILL(?:ED)?): Match USE BY or DATE FILLED or DATE FILL
.*: Match 0 or more of any characters
(?P<date>\d{1,2}[-/]\d{1,2}[-/]\d{2,4}): Match a date string using / or - as delimiter

answered Jan 2, 2021 at 6:31

anubhava

790k67 gold badges603 silver badges671 bronze badges

Sign up to request clarification or add additional context in comments.

Collectives™ on Stack Overflow

Python regex group matches shows extra empty string

1 Answer 1

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

Comments

Your Answer

Sign up or log in

Post as a guest

Related